When coughing, swallowing, vomiting, holding the breath tightly, etc., these folds of mucous membrane close over the true bands, often completely, and thus shut up for the moment the whole of that space between the bands known as the glottis, or glottic chink, to which reference was made in a previous chapter as the space through which the air finally gains access to the lungs.

It will be noted that Madame Seiler spoke of the vocal bands (cords) proper as the "ligamentous glottis," and included in the "glottis" the arytenoid cartilages themselves, or, at all events, that part of them, their lower anterior angles, known as the vocal processes (or extensions), to which the vocal bands proper are attached.

In less than 35 milliseconds the glottis (a tissue flap that guards the entrance to the trachea, or windpipe) closes and produces the characteristic sound as the incoming air is blocked from entering the trachea.